Six Rules via the Financial Times:

1. Be curious about others; 
2. Take off your mask; 
3. Empathize with others; 
4. Get behind the job title; 
5. Use adventurous openings; 
6. Have courage.

Compliment this with ten techniques for building quick rapport with anyone.

In 44BC Cicero wrote the following rules, distilled for us by The Economist:

The rules we learn from Cicero are these: speak clearly; speak easily but not too much, especially when others want their turn; do not interrupt; be courteous; deal seriously with serious matters and gracefully with lighter ones; never criticise people behind their backs; stick to subjects of general interest; do not talk about yourself; and, above all, never lose your temper.

Probably only two cardinal rules were lacking from Cicero’s list:

1. Remember people’s names, and

2. Be a good listener.

Creating an open dialogue:

We wanted to open dialogue and increase understanding through a balance of advocacy and inquiry. This approach includes three key tools: (1) advocating your own position and then inviting responses (e.g., “This is how I see the situation, and why; to what extent do you see it differently?”); (2) paraphrasing what you believe to be the other person’s view and inquiring as to the validity of your understanding (e.g., “It sounds to me like your argument is this; to what extent does that capture your argument accurately?”); and (3) explaining a gap in your understanding of the other person’s views, and asking for more information (e.g., “It sounds like you think this acquisition is a bad idea. I’m not sure I understand how you got there. Could you tell me more?”).

Yes, and …Via The Plateau Effect: Getting from Stuck to Success:

Anyone who has ever taken a class in improvisation has learned the “yes, and…” technique. Ever wonder what keeps a great improv troupe from falling silent? It’s simple. No one is allowed to say no. Whatever is said, the other actors are forced to accept it and build upon it. This conversational style pays immediate dividends. Instead of creating blocks, or, “stops” to the chatter, it allows group discussions to build on each other.